The present invention relates to an optical disk apparatus and optical head thereof in which disk plates of different thickness from the side in the face of the optical head to the information recording surface (hereinafter, the thickness) such as high density recording or play back disks and Compact Discs (CD) may be played back and/or recorded.
An example of the optical disk apparatus of the prior art in which one single apparatus being capable of playing back or reading/writing disks having different thickness is disclosed in the Japanese Patent Laid-Open Hei 4-95224, which apparatus is used for converging laser light beam into an optical disk recording layer without the need of interchanging objective lens for each respective of disk plates having different thicknesses.